cancer - quiz #3 Flashcards
most basic level of cancer
abnormal cells that uncontrollably divide & never die
-accumulate together into clumps called “tumors” or flow freely through bone marrow, lymphatic fluid, body tissues & blood
how does cancer spread
throughout body via bloodstream, invading other tissues
-can be compared with a parasite that drains energy from body & competes for its nutrients
NEOPLASIA
“new growth” NOT controlled by normal regulatory mechanisms – cells do not contribute to organism, but draw on its resources
-masses form together into clumps called “neoplasms” or “tumors”
-may be malignant/ benign
Study of malignant cancer
ONCOLOGY
6 UNIQUE CHARACTERISTICS of cancer cells that are different than any other cell in body
- Anaplasia
- Anchorage independent
- Lack of contact inhibition
- Immortality
- Angiogenesis
- Genetic instability
ANAPLASIA
-cells undifferentiated → have not developed into particular cells yet
-NO function (other than reproducing)
-variety of shapes & sizes
-unusually large nuclei & bear little/ no resemblance to normal cells in surrounding tissues
ANCHORAGE INDEPENDENT
-cancer cells detach from bottom of culture flask, floating away in soft agar & form new colonies (unlike normal cells that are anchored)
-encourage cancer cells to invade nearby tissue & expand outwards to go elsewhere in body
LACK OF CONTACT INHIBITION
-when normal cells contact each other/ contact basement membrane, attempt to move apart to avoid damage/ collision
= “contact inhibition
-cancer cells do not possess this normal cell trait
IMMORTALITY
-reverse shortening of telomeres & lengthen telomeres every time they divide, making them immortal
-may continue to divide for years with right conditions
ANGIOGENESIS
-tumors need blood supply if they grow larger than few millimeters
-cancer cells have ability to secrete chemical stimulators that stimulate angiogenesis in nearby tissues
-develop vascular network to bring oxygen & nutrients for continued growth & expansion of cancerous cells & tumor
GENETIC INSTABILITY
-divide continuously & have tendency toward genetic alteration during cell division
-causes genetic damage
-cancer often caused by damage to genes that help control cancer in body like tumor suppressors
BIOCHEMISTRY (biology of tumor cell)
cancerous cell requires less oxygen – has no other function besides reproducing, accumulating & spreading – may acquire new functions (anaplasia) – very simple metabolism
GROWTH PROPERTIES (biology of tumor cell)
survives easily, requires less nutrients – all energy goes to growth & reproduction – some cancer cells are immortal, lack contact inhibition, have anchorage dependant growth, do not require external growth factors – some tumors produce their own = “autonomous”
cancerous cell growth has 3 distinct features that differentiate it from normal cell growth
AUTONOMOUS
EXCESSIVE
DISORGANIZED
AUTONOMOUS (cancer - cell growth)
dependant of normal growth factors & inhibitors
EXCESSIVE (cancer - cell growth)
does not respond to normal growth & division regulators
DISORGANIZED (cancer - cell growth)
tissues formed are irregular
clinical classification of tumors (determine malignant/ benign)
looks at clinical presentation & outcomes of cancer
histologic classification of tumors (determine malignant/ benign)
looks under microscope at cancerous tissues/ cells, determines what type of cells the cancer is made up of
non cancerous tumors & may arise from any tissue type
BENIGN
cancer defined by limited growth potential with good prognosis/ outcome – curable
MALIGNANT
cancer is defined by uncontrollable growth – will eventually kill host
-causing metastatic cancer
METASTASIS
process where tumor cells move from one site in body to another – only malignant cells can spread
3 main pathways for spread:
-Lymphatic system
-Bloodstream (hematogenous spread)
-Seeding of surfaces of body cavities (close by)
METASTATIC CASCADE
-as tumor grows, some cells develop ability to metastasize, some do not
-enter lymphatic system, bloodstream, close-by cavities – fluid carry tumor cells away to different site, they attach & form tumor
-cancerous cells must escape immune systems attack with T-lymphocytes, natural killer & macrophages
-must form new blood supply to bring oxygen & nutrients for new tumors to grow = angiogenesis
CLASSIFICATION OF TUMORS
Mesenchymal tumors
Epithelial tumors
Blood cell & lymphocyte tumors
Tumors of glial cells
Germ cell tumors
FIBROMA (benign tumors from mesenchymal cells)
from fibroblasts
CHONDROMA (benign tumors from mesenchymal cells)
from cartilage
LIPOMA (benign tumors from mesenchymal cells)
from adipose tissue
LEIOMYOMA (benign tumors from mesenchymal cells)
from smooth muscle cells
RHABDOMYOMA (benign tumors from mesenchymal cells)
from striated muscle cells
OSTEOMA (benign tumors from mesenchymal cells)
from bone
benign tumors from epithelial cells - ADENOMA
-Tubular / villous – GI tract (polyps)
-Papillomas – skin, urinary bladder, mouth, larynx
-Cystadenomas – forms cysts
malignant tumors of mesenchymal cell
(named from root of cell type + “sarcoma”)
-Fibrosarcoma – malignant tumor from fibroblasts
-Chondrosarcoma – malignant tumor from cartilage
-Liposarcoma – malignant tumor from fat
malignant tumor of epithelial cells
(called carcinomas)
Squamous cell carcinoma
malignant tumor of glands & ducts
(called adenocarcinomas)
Malignant tumors of embryonic cells called blastomas
2 methods of staging/ grading tumors
- TNM tumor staging
- Grading a tumor
TNM – TUMOR STAGING
clinically assessing extent to tumor spread – X-rays, biopsy, surgery
-size of primary tumor (T)
-presence/ absence of lymph node involvement (N)
-distant metastasis (M)
TUMOR GRADING
based on histologic examination of tumor cells
-Grade I: well differentiated cells (benign)
-Grade II: moderately well differentiated cells
-Grade III: undifferentiated cells (malignant)
EXOGENOUS (cause of cancer, carcinogen)
from outside world, chemical, physical agents, viruses
ENDOGENOUS (cause of cancer, carcinogen)
from within us, in genome of each other (oncogenes)
systemic symptoms
-Cachexia (generalized wasting & weakness)
-Weight loss
-Thrombosis
-Loss of appetite (anorexia)
-Paraneoplastic syndromes (caused by cancer cell secretions)
EPIDEMIOLOGY OF CANCER: study of cancer in human populations
Incidence: # of new cases over specific period
Prevalence: # of all cases in specific population over specific period
Mortality: # of deaths in specific population over specific period
